(1) Field of the Invention
The present invention relates to a process for the preparation of a powdery calcium cellulose glycolate and a use of the powdery calcium cellulose glycolate as a disintegrator for solid pharmaceutical preparations.
(2) Description of the Prior Art
Calcium cellulose glycolate is widely used as a disintegrator for solid pharmaceutical preparations, because it is tasteless, odorless and white-colored and has many merits such as excellent disintegrating property, excellent degree of swelling and excellent compression molding property. It is commercially available e.g., under the trade name ECG-505 (from NICHIRIN CHEMICAL INDUSTRIES LTD. in Japan). However, it is pointed out that, when a disintegrator is used in a large amount, the hardness of the resulting solid pharmaceutical preparation becomes short.
The calcium cellulose glycolate now available commercially is prepared basically according to the process described in the specification of Japanese Patent Publication No. 7960/1968. That is, the calcium cellulose glycolate is prepared by reaction of a purified cellulose glycolic acid having a degree of substitution by carboxymethyl group per anhydrogluocse unit of 0.2-0.8, with calcium carbonate under such conditions that the water content during the reaction is 30-80%, which is followed by drying, pulverizing and sieving. In said specification, various calcium reagents to be reacted with cellulose glycolic acid are mentioned. However, it is described that calcium acetate, calcium phosphate and calcium chloride are not employed because acetic acid, phosphoric acid and hydrochloric acid are formed, respectively, by neutralization reaction and calcium hydroxide is also not employed because, on neutralization reaction, the reaction system becomes viscous and shows partical coagulation. Thus, it is described that only calcium carbonate can be used practically.